Technical Field
The present invention relates to a hollow fiber membrane supported liquid-phase microextraction (HFM-LPME) method for determining sulfur compound concentration in a hydrocarbon sample and a hollow fiber membrane supported liquid-phase microextraction (HFM-LPME) system for determining sulfur compound concentration in a hydrocarbon sample.
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Fossil fuel is the main source of world wide's energy, petroleum products such as diesel is extensively used as a fuel for transportation systems (C. Song, Catalysis Today 86 (2003) 211; J. H. Kim, X. Ma, A. Zhon, C. Song, Catal Today 111 (2006) 74—each incorporated herein by reference in its entirety). Crude oil consists of more than 200 sulfur compounds which includes derivatives of thiophenes and benzothiophene in the range of 0.01 to 3% as a total sulfur (C. Song, X. Ma, Appl. Catal. B Environmental, 41 (2003) 207; P. T. Vasudevan, J. L. Firrro, Catalysis Rev.—Science Eng. 38(1996)161; M. R. Gary F. Khorasheh, Ind. Eng. Chem, 17 (1978) 196; S. Zhang, D. Liue, W. Deng, Energy Fuels 21 (2007) 3057—each incorporated herein by reference in its entirety). The sulfur content in petroleum product increases along with the boiling points of the distillate fractions (P. S. Tam, J. W. Eldridge, Ind. Eng. Chem. Res. 29 (1990) 321; A. Stanislaus, A. Marafi, M. S. Rana, Catalysis Today 153, (2010) 1—each incorporated herein by reference in its entirety). The sulfur compounds in petroleum products significantly damage the environmental and also leads to undesirable effects in refining processes such as deactivation of catalysts (A. Marafi, A. Al-Hindi, A. Stanislaus, Fuel Process. Technol. 88 (2007) 905; X. L. Ma, K. Sakanishi, I. Mochida, Ind. Eng. Chem. Res. 34 (1995) 748—each incorporated herein by reference in its entirety). Sulfur compounds generate SOx and particulate emissions during combustion process (X. Ma, S. Velu, J. H. Kim, C. Song, Appl. Catal. B Environ. 56 (2005)137; M. M. Mariq, R. E. Chase, N. Xu, P. M. Laing, Environ. Sci. Technol., 36 (2002) 283; A. Sydbom, A. Blomberg, S. Parnia, N. Stenfors, T. Sandstrom, S.- E. Dahlen, Eur. Respir. J. 17 (2001) 733; I. Vergov, I. Shishkova, Petrol. Coal. 51 (2009) 136—each incorporated herein by reference in its entirety). The presence of SOx in the exhaust gas is also one of the leading causes of acid rain (L. Hylander, M. Goodsite, Sci. Tot. Environ. 368 (2006) 352; Y. Shiraishi, T. Hirari, Eng. Chem. Res. 37 (1998) 218—each incorporated herein by reference in its entirety). To improve the air quality, environmental regulations have been implemented in many parts of the world to reduce the SOx by restricting the emission level to less than 10 mg L−1 (N. Gupta, P. Roychoudhury, Appl. Microbiol. Biotechnol. 66 (2005) 356; F. Ali, A. Malki, Fuel Process. Technol. 42 (1995) 35; J. D. Holbery, K. R. Seddon, Green Chem 10 (2008) 87; S. T. Oyama, J. Catal. 216 (2003) 343—each incorporated herein by reference in its entirety). Analytical methods capable of detecting sulfur in low concentrations from complex sample matrices are highly demanding.
Quantitative determination of sulfur compounds in crude oils are a challenging task due to the complicated sample matrix. The American Petroleum Institute (API) gravity and viscosity of are higher for crude oils and diesel, traditional sample preparation methods are not effective. Based on the physical and chemical properties of the samples several American Society for Testing and Materials (ASTM) methods based on gas chromatography methods have been reported for quantitative measurement of sulfur compounds (C. L. Hemler, L. F. Smith, in: R. A. Meyers (Ed.), Handbook of Petroleum Refining Processes, McGraw-Hill, 2004—incorporated herein by reference in its entirety). To avoid the sample preparation prior to sample introduction into GC system, crude oils were simply diluted with organic solvents (P. K. Niccum, C. R. Santner, in: R. A. Meyers (Ed.), Handbook of Petroleum Refining Processes, McGraw-Hill, Texas, 2004—incorporated herein by reference in its entirety). The metallic constituents (Ni and V could be as high as 1000 μg g−1) that also cause the greatest concern for GC analysis (J. G. Speight, The Chemistry and Technology of Petroleum, Taylor & Francis, New York, 2006—incorporated herein by reference in its entirety). Selectivity of the ASTM method relates on the instrumental conditions for example, ASTM D5623, ASTM D3328, ASTM D6228 methods were reported for sulfur analysis in petrochemical matrices using GC with pulsed flame photometric detector (PFPD) and ASTM D5504 was reported for GC with sulfur chemiluminescence detection (Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Chemiluminescence, ASTM D5504 (05.06), ASTM, Philadelphia, Pa., 2002; ASTM Standard D 3328-06, Standard Test Method for Comparison of Waterborne Petroleum Oils by Gas Chromatography, ASTM International, West Conshohocken, Pa., www.astm.org; ASTM Standard D 6228-98, Standard Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Flame Photometric Detection, ASTM International, West Conshohocken, Pa., www.astm.org; ASTM Standard D 5623-94, Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection, ASTM International, West Conshohocken, Pa., www.astm.org; ASTM Standard D 5623-94, Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection, ASTM International, West Conshohocken, Pa., www.astm.org—each incorporated herein by reference in its entirety). All these ASTM methods, samples were directly analyzed with series of dilutions. Large volume dilution may lead to poor quantitation and the particulates in crude oil might contaminate the GC injection port (Paola A. Mello, Juliana S. F. Pereira, Marcia F. Mesko, Juliano S. Barin, Erico M. M. Flores, Anal. Chim. Acta. 746 (2012) 15—incorporated herein by reference in its entirety).
More environmentally-friendly alternatives to conventional methods have been disclosed for determination of sulfur compounds in other sample matrices which includes solid-phase microextraction, dispersive liquid-liquid microextraction, and solid-phase extraction (U. C. Meier, J. Chromatogr. A. 1286 (2013) 159; V. P. Jofré, M. V. Assof, M. L. Fanzone, H. C. Goicoechea, L. D. Martinez, M. F. Silva, Anal. Chim. Acta. 683 (2010) 126; E. Kabir, K- H. Kim, Microchem. J. 103 (2012) 42—each incorporated herein by reference in its entirety). However, these methods have not been investigated for the complex sulfur compound detection in complex sample matrices such as crude oil and heavy diesel samples.
Hollow fiber membrane supported liquid-phase microextraction (HFM-LPME) has been reported for extraction of various classes of analytes from various complex sample matrices such as beverages, urine, soil, waste water, and oil spills in sediment samples (Xiong J, Hu B. J Chromatogr A. 1193 (2008) 7; Li Xu, C. Basheer, H. K. Lee, J. Chromatogr A. 1216 (2009) 701; Q. Xiao, C. Yu, J. Xing, B. Hu, J. Chromatogr A. 1125 (2006) 133—each incorporated herein by reference in its entirety). HFM-LPME is a fast, simple and inexpensive solvent minimized sample preparation method. The LPME combines extraction, sample cleanup and sample preconcentration in a single step. The porous HFM membrane acts as a filtering device that eliminates interfering particles. After extraction the clean extract is suitable for direct instrumental analyses. Thus, HFM-LPME has the potential for selective extraction of analytes from complex matrices. The technique is based on the distribution of analytes between microliter volumes of organic phase (acceptor phase) and the sample (donor phase).
The current disclosure describes a single step HFM-LPME for the determination of low and high concentrations of sulfur compounds in crude oils and diesel samples.